Randomly my computer's HDMI output (running Debian 8) doesn't output anything to HDMI (my screen says "no signal"). Other times it does. The only thing I can say is that if it works just after boot, it works always. Otherwise it doesn't work at all and I have to restart my machine.

I made some research and apparently nothing is wrong:

  • I have an NVidia graphical card supporting Optimus technology. So I'm using bumblebee with proprietary nvidia software uninstalled
  • lsmod | grep 'hdmi' returns several items:
snd_hda_codec_hdmi     45118  1 
snd_hda_codec         104463  5 snd_hda_codec_realtek,snd_hda_codec_hdmi,snd_hda_codec_generic,snd_hda_intel,snd_hda_controller
snd_pcm                88662  4 snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel,snd_hda_controller
snd                    65244  18 snd_hda_codec_realtek,snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_pcm,snd_hda_codec_generic,snd_hda_codec,snd_hda_intel

How can I diagnostic what's wrong with my HDMI output?

  • Running Debian 11 (testing) at the time, I had the "no signal" problem until I ran the following command: dbus-launch dolphin The following tip gave me the trick: forum.manjaro.org/t/…
    – Olivier
    Jun 6, 2020 at 9:16
  • @Olivier The page you've rederred to doesn't exist anymore. Could you elaborate, please? I've just updated to Debian 11 and my HDMI output doesn't work. Mar 12, 2021 at 2:33


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